A Belgian man serving a life sentence for rape and murder will be allowed to have doctors end his life, after a landmark ruling.

Unable to control his violent sexual urges, Frank Van Den Bleeken, who is 50, argued he would never be freed.

The decision follows a three-year legal battle by the prisoner, who was convicted in the 1980s.

The ruling is the first involving a prisoner since the assisted dying law was introduced in Belgium 12 years ago.

Van Den Bleeken will soon be transferred to a hospital where the medical procedure will take place, his lawyers told reporters.

"But I cannot say when or where that will happen," Jos Vander Velpen added.

Die 'with dignity'

Van Den Bleeken first requested euthanasia in 2011, citing "unbearable psychological anguish", but Belgium's Federal Euthanasia Commission wanted to consider every possible treatment option, before consenting to such a measure.

Piers Scholfield, BBC News, Brussels

The number of euthanasia cases in Belgium has gradually risen each year since the law was first introduced in 2002 - and most are now uncontroversial, concerning older, terminally ill people. But new ground has been broken several times recently, and the legislation is not without its critics.

In January 2013, Belgian media reported the deaths of Marc and Eddy Verbessem - 45-year-old identical twins who were deaf and asked for euthanasia after finding out that they would go blind as a result of a genetic disorder.

In a case which received less coverage, Nathan Verhelst died last October. He was a transsexual and asked to die after several failed sex-change operations.

Belgian senator Els van Hoof called these cases deeply troubling. She was on the losing side of a vote early this year, when the Belgian senate approved a bill lifting all age restrictions on euthanasia - but she and others did manage to alter the law to apply only to children who were terminally ill.

Supporters have called euthanasia the "ultimate gesture of humanity". Critics such as Ms Van Hoof say how the law is interpreted could lead to a slippery slope - and Mr Van den Bleeken's case - a prisoner, not terminally ill but apparently in permanent psychological pain - might well lead to further criticism.

The European Court of Human Rights has criticised Belgium several times for its failure to properly treat mentally ill prisoners, the BBC's Piers Scholfield reports.

Image caption
The Belgian parliament legalised euthanasia in 2002, the second country in the world to do

Belgium's euthanasia laws hit the headlines earlier this year when they were extended to cover children who are terminally ill.